Derived units are defined by combination of other units. Derived units are used for quantities other than those corresponding to the base units, such as hertz (s-1) for frequency, Newton (kg.m/s2) for force. Derived units based directly on base units are usually preferred for quantities other than the fundamental quantities within a system. If a derived unit is not the preferred unit, the gml:ConventionalUnit element should be used instead.The gml:DerivedUnit extends gml:UnitDefinition with the property gml:derivationUnitTerms.
The attribute gml:id supports provision of a handle for the XML element representing a GML Object. Its use is mandatory for all GML objects. It is of XML type ID, so is constrained to be unique in the XML document within which it occurs.
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<element name="DerivedUnit" type="gml:DerivedUnitType" substitutionGroup="gml:UnitDefinition"><annotation><documentation>Derived units are defined by combination of other units. Derived units are used for quantities other than those corresponding to the base units, such as hertz (s-1) for frequency, Newton (kg.m/s2) for force. Derived units based directly on base units are usually preferred for quantities other than the fundamental quantities within a system. If a derived unit is not the preferred unit, the gml:ConventionalUnit element should be used instead. The gml:DerivedUnit extends gml:UnitDefinition with the property gml:derivationUnitTerms.</documentation></annotation></element>